These are excerpts and elaborations from my book "The Nature of Consciousness"
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The New Materialism:
Naturalistic Dualism The Australian philosopher
David Chalmers believes that consciousness is
due to "protoconscious" properties that must be ubiquitous in matter
and that "psychophysical" laws, not of the "reductionist"
kind that Physics employs, will account for how conscious experience arise from
those properties. There is, instead, nothing mysterious about our cognitive
faculties, such as learning and remembering: they can be explained by the
physical sciences the same way these sciences explained physical phenomena. In a sense, Chalmers changed
the scope of the mind-body problem, by enlarging the "body" to
include the brain and its cognitive processes, and by restricting
"mind" to conscious experience. Cognition migrates to the body.
Consciousness, on the other hand, is truly a different substance, or, better, a
different set of properties, and cannot indeed be explained by the "natural"
laws of the physical sciences. The study of consciousness requires a different
set of laws, because consciousness is due to a different set of properties. Chalmers contends that
mental (or, better, brain) activity is more than just conscious experience.
States of the brain cause behavior. For
example, I drink because I am thirsty, I move my hands because I want to grab
an object, I buy a plane ticket because I believe the fare will go up. These
"mental" states may or may not be conscious. Chalmers therefore distinguishes between the
conscious experience, that he calls the "phenomenal properties of the
mind", and the mental states that cause behavior, that he calls the
"psychological properties of the mind" (that is cognition). In other words, phenomenal states deal with
the first-person aspect of the mental, whereas psychological states deal with
the third-person aspect of the mental. Psychological properties
have, by his definition, a "causal" role in determining behavior.
Whether a psychological state is also a phenomenal (conscious) state does not
matter from the point of view of behavior.
What conscious states do is not clear, but we know that they exist
because we "feel" them. Mental properties can
therefore be divided into psychological properties and phenomenal properties.
These two sets can be studied separately. It turns out that psychological
properties (such as learning and remembering) have been and are studied by a
multitude of disciplines, such as Biology and Neurology, and in a fashion not too
different from physical properties of matter (given their "causal"
nature), whereas phenomenal properties constitute the "hard"
problem. A psychological property
causes some behavior, no less than most material properties. A phenomenal
property is a fuzzier object altogether. Chalmers also distinguishes awareness
and consciousness: awareness is the "psychological" aspect of
consciousness. Whenever we are aware, we also have access to information about
the object we are aware of. Awareness
is that access. It is a psychological state that has a "causal"
nature. "Consciousness" is a
term more appropriately reserved for the phenomenal aspect of consciousness
(for the emotion, for the feeling). Chalmers is, de facto,
separating the study of cognition from the study of consciousness. Cognition is
a psychological fact, consciousness is a phenomenal fact. Psychological facts,
by virtue of their causal (or functional) nature, can actually be explained by
the physical sciences. It is not clear,
instead, what science is necessary to
explain consciousness. To start with, Chalmers focuses on the notion of
supervenience. Chalmers goes to a great
extent to clarify the theory of supervenience.
A set Y of properties supervenes on a set X of properties if any two
systems that are identical by properties X are also identical by properties
Y. For example, biological properties
supervene on physical properties: any two identical physical systems are also
identical biological systems. "Logical"
supervenience (loosely, "possibility") is a variant of supervenience:
some systems could exist in another world (are "logically" possible),
but do not exist in our world (are "naturally" impossible). Elephants with wings are logically possible,
but not naturally possible. Systems
that are naturally possible are also logically possible, but not viceversa. For
example, any situation that violates the laws of nature is logically possible
but not naturally possible. Natural supervenience occurs
when two sets of properties are systematically and precisely correlated in the
natural world. Logical supervenience
implies natural supervenience, but not viceversa. In other words, there may be worlds in which two properties are
not related the way they are in our world, and therefore two naturally
supervenient systems may not be logically supervenient. Chalmers then argues that
most facts supervene logically on the physical facts: if they are identical
physical systems, then they are identical, period. There are few exceptions and consciousness is one of them. Consciousness is not logically supervenient
on the physical. Thus Chalmers concludes that consciousness
"cannot" be explained by the physical sciences (more appropriately,
cannot be explained "reductively"). But Chalmers does not conclude
that consciousness cannot be explained tout court: only that it cannot be
explained the way the physical sciences explain everything else, i.e. by
reducing the system to ever smaller parts.
Chalmers leaves the door open for a "nonreductive" explanation
of consciousness. Chalmers does not rule out
"monism", the theory that there is only one substance; he only rules
out that the one substance of this world is matter as we know it with the
properties we currently know. Chalmers theory of
consciousness is a variant of "property dualism": there are no two
substances (mental and physical), there is only one substance, but that
substance has two separate sets of properties, one physical and one mental. Conscious experience is due to the mental
properties. The physical sciences have
studied only the physical properties.
The physical sciences study macroscopic properties like
"temperature" that are due to microscopic properties such as the
physical properties of particles. Chalmers advocates a science that studies the
"protophenomenal properties" of microscopic matter that can yield the
macroscopic phenomenon of consciousness. Electromagnetism could not
be explained by "reducing" electromagnetic phenomena to the known
properties of matter: it was explained when scientists introduced a whole new
set of properties (and related laws): the properties of microscopic matter that
yield the macroscopic phenomenon of electromagnetism. Similarly, consciousness
cannot be explained by the physical laws of the known properties but requires a
new set of "psychophysical" laws that deal with "protophenomenal
properties". Consciousness
supervenes naturally on the physical: the "psychophysical" laws will
explain this supervenience, i.e. they will explain how conscious experiences
depend on physical processes. Chalmers emphasizes that
this applies only to consciousness.
Cognition is governed by the known laws of the physical sciences. Chalmers then turns to the relationship between cognition and
consciousness. Phenomenal (conscious)
experience is not an abstract phenomenon: it is directly related to our
psychological experience. Consciousness interacts with cognition and that
interactaction gets expressed via what Chalmers calls "phenomenal judgements"
("I am afraid", "I see", "I am suffering"). These are acts that belong to our
psychological life (to cognition) but are about our phenomenal life
(consciousness). Chalmers is faced with a
paradox: phenomenal judgements, that are about consciousness, belong to
cognitive life, therefore can be explained reductively, but he just proved that
consciousness cannot be explained reductively.
The way out of the paradox is to assume that consciousness is not relevant,
that we can explain phenomenal judgements even if/when we cannot explain the
conscious experience they are about, i.e. the explanation does not depend on
that conscious experience, i.e. that feeling or emotion is irrelevant. Chalmers cautions that this conclusion
does not necessarily imply that consciousness (as in "free will") is
irrelevant for behavior, but it surely does smell that way. If we can explain behavior about
consciousness without explaining consciousness, it is hard to believe that
behavior requires consciousness. Chalmers takes these facts
literally: our statements about consciousness are part of our cognitive life,
and therefore can be explained quite naturally, just like any other behavior. I
speak about my feelings the same way i raise a hand. There is a physical
process that explains why i do both. It
also happens that we "are" conscious, not just that we talk about it,
and that part cannot be explained (yet).
If we had a detailed understanding of the brain, we could predict when
someone would utter the words "I feel pain". So Chalmers believes that our talk about
consciousness will be explained just like any other cognitive process, just
like any other bodily process. This is
not the same as explaining the conscious feelings themselves, and it leaves
open the option that feelings are but an accessory, an evolutionary accident, a
by-product of our cognitive life with no direct relevance to our actions. Chalmers also offers an
explanation of phenomenal judgement based on the theory of information. After
all, his definition of "cognition" is pretty much that of
"information processing": cognition is the processing of information,
from the moment it is acquired by the senses to the moment it is turned into
bodily movement. Information is what
"pattern" is from the inside. Consciousness is information about the
pattern of the self. Information becomes therefore the link between the
physical and the conscious. Since information is
ubiquitous, he also gets entangled in the question whether everything has feelings.
If experience is ultimately due to information, there is no reason why anything
would not be associated with "experience". Just like every other physical property that we know to be
widespread in the universe, there is no reason why "experience" (defined
as the macroscopic effect of "protophenomenal properties") should not
be widespread. Objects that implement
an information-processing system may well have a degree of consciousness. Chalmers' "natural dualism" is
therefore a close relative of "panpsychism". Furthermore, if information
leads to experience, there must be a lot more experience than we
"feel" because the brain processes a lot more information than we are
aware of. But then parts of the brain may have experience that does not travel
to the "i". The "i" is not necessarily all that is
experienced by the brain. The "i" may simply be a chunk of coherent
information out of the many that arise all the time in the brain. Ultimately, David Chalmers believes that it makes no sense
to talk of pieces of consciousness. Consciousness "is" the experience
of being the subject, so, by definition, it is a unity: it is all of which I am
the subject at a certain time. This has implications for any theory of
consciousness, because the reductionist approach (splitting the problem into
smaller problems) is, by definition, doomed to failure: consciousness cannot be
split lest you lose precisely consciousness, and then you are no longer
analyzing consciousness. Consciousness can only be studied as the state of
being the subject, which is fundamentally different from the study of how the
brain is enabled to integrate different processes. What is needed is a holistic
approach to consciousness. Back to the beginning of the chapter "A Physics Of Consciousness" | Back to the index of all chapters |
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